Hi,
I would like to discuss different blur radii for the horizontal and vertical direction. I got a request to add this for the blur() function in Filter Effects[1]. Since Filter Effects, CSS Text Decoration[2] and CSS Background and borders[3] use (fairly) the same syntax, I think it makes sense to discuss this in a global spec scope.
Sadly the shadow syntax does not use comma separation, which makes syntax changes a bit difficult. Maybe we can still come up with a proposal:
<shadow> = inset? && [ [<length>{2} [<length>[/<length>]?] <length>?] && <color>? ]
This may look complicated but isn't that hard:
box-shadow: 64px 64px 12px/6px 40px rgba(0,0,0,0.4);
Would create a black shadow with a horizontal blur radius of 12px and a vertical blur radius of 6px. Both blur radii are separated by "/". If the second parameter is missing, the vertical blur is equal to the horizontal blur. Which makes it backwards compatible.
All values need to be animatable separately.
Greetings,
Dirk
[1] https://dvcs.w3.org/hg/FXTF/raw-file/tip/filters/index.html#FilterFunction
[2] http://dev.w3.org/csswg/css-text-decor-3/#text-shadow-property
[3] http://dev.w3.org/csswg/css3-background/#box-shadow